The cosmological co-evolution of supermassive black holes, AGN and galaxies

We model the cosmological co-evolution of galaxies and their central supermassive black holes (BHs) within a semi-analytical framework developed on the outputs of the Millennium Simulation citep{croton2006,delucia2007}. In this work, we analyze the model BH scaling relations, fundamental plane and mass function, and compare them with the most recent observational data. Furthermore, we extend the original code developed by citet{croton2006} to follow the evolution of the BH mass accretion and its conversion into radiation, and compare the derived AGN bolometric luminosity function with the observed one. We find, for the most part, a very good agreement between predicted and observed BH properties. Moreover, the model is in good agreement with the observed AGN number density in 0< z<5, provided it is assumed that the cold gas fraction accreted by BHs at high redshifts is larger than at low redshifts